Critical evaluation of factors affecting the operation of dense medium cyclones treating medium coking coals

The efficiency of a bank of dense medium cyclones treating medium coking co al in the size range of - 13 + 0.5 mm. was evaluated. Performance indicator s for evaluating the efficiency of the separation were identified. Various variables affecting the efficiency of the dense medium cyclones (DMC) were examined to identify those that affect the DMC operation and new levels of the parameters identified to bridge the gap between the actual and the idea l. The studies showed that for coals having a high level of NGM, feed rate could be one of the critical parameters affecting the efficiency of separat ion. Feed rate and the spigot diameter were used to reduce the EP and for c oarser adjustments of cutpoints. Mathematical model for the cyclones was developed using the generalised dis tribution curve, represented by the equation of the form: y = 100[exp - (x - x(0))(a)/b] where y is the percent distribution of clean coal corresponding to a reduce d specific gravity x, x is defined as Sg/Sg(50), and a, b and x(0) are cons tants. Corelations were then developed relating the coefficient of separation (sho wing the separation efficiency) and the EP to the design and operating vari ables of the cyclones. (C) 2001 Elsevier Science B.V. All rights reserved.